That's impossible, as there isn't anything to set how many buried coins are in that thing. Also, the characters can't take two or more object at once and this feature isn't even in SMB2.
Another thing you found do is make a layer with a bunch of coins in the same spot, hide it, and use the grass with nothing (acessable via the "The Lakitus are Throwing Lakitus!" tab) and have it so when it dies it shows the layer. I hope that made sense.